Pressure transmission catheter with sheath

Inventors

Zwiers, Lynn M. • Lichtscheidl, Gregg • Rudie, Eric

Assignees

Harvard Bioscience Inc

Abstract

Methods and apparatus for sensing pressure are disclosed. One disclosed pressure measuring device comprises a pressure transmission catheter including a stem portion and a sheath fixed to the stem portion. The disclosed sheath comprises a wall defining a cavity that is in fluid communication with a stem lumen defined by the stem portion. The disclosed sheath has a first transverse extent and a second transverse extent that is different from the first transverse extent.

Core Innovation

The invention relates to an implantable pressure sensor that includes a pressure transducer with a mechanical sensing input and an electrical output providing an indication of a sensed pressure level. The system further includes an elongate pressure transmission catheter comprising an outer covering that forms an inner cavity and a pressure transmission substance contained within the inner cavity. The pressure transmission catheter is positioned within an environment whose pressure level is to be indicated by the electrical output.

At least a portion of the outer covering is formed to have a cross-sectional shape that is a partially flattened circle, or more generally a non-circular cross-sectional shape. External pressure forces acting upon an outside surface of the portion of the outer covering compress the pressure transmission substance within the inner cavity. The pressure transmission substance conveys the compressed pressure to the mechanical sensing input of the pressure transducer to provide an indication of the pressure level.

The disclosed sheath geometry includes a partially flattened intermediate portion between two cylindrical waist portions having different first and second transverse extents and an axial extent larger than either transverse extent. The sheath geometry is characterized by major sides and minor sides with differing convexity and differing first and second radii to create pressure-sensitivity differences. A strut tubular member provides increased axial rigidity and defines a strut lumen with cutouts receiving corresponding sheath portions, and the document further states that a pressure transmitting fluid is disposed to convey pressure to a pressure sensor.

Claims Coverage

The partial content includes two independent claims. Both claims share the same core pressure-sensing architecture and differ primarily in the outer-cover cross-sectional geometry used to compress and convey external pressure to the transducer.

Across the two independent claims, the inventive focus is using a partially flattened-circle or a non-circular cross-sectional portion of the catheter outer covering so that external pressure compresses the pressure transmission substance in the inner cavity and conveys that compressed pressure to the transducer’s mechanical sensing input to indicate environmental pressure.

Stated Advantages

Documented Applications